Is there a simple python script for xpub generation from private key

Question

I need a python script to verify, in an air gapped system, that my 24-word (or 12-word) mnemonic seed indeed generates the xpub that my wallet is showing me.

Is there a simple script that does that, having minimal dependencies?

UPDATE:

based on the answer below using https://github.com/trezor/python-mnemonic, I did

def main() -> None:
    import sys
    m = Mnemonic("english")
    seed = Mnemonic.to_seed("my 12 words")
    pubkey = Mnemonic.to_hd_master_key(seed)
    print(pubkey)

but I get

xprv...

and no pubkey.

How do I get the master pub key?

Answer 1

Using this library which is a pure python library with no dependencies (disclaimer: I am the author)

>>> from cryptotools import Xprv

>>> xprv = Xprv.from_mnemonic('assist excess fox blossom trouble cry must segment arrive stereo weather april pudding tuna change')

>>> xpub = xprv.to_xpub()

>>> xpub.encode()
'xpub661MyMwAqRbcGSaJ8ymCnwWbZzUgRB9XSAGoAvJc92oorJqzfyTPNQCEzqetVjofVs6DjXEPgR62vGP8UsSL4HFXLcRHdBbcDZ7DgyZea59'

Answer 2

Yes, I'd say the simplest way is to use python bip39 implementation of trezor, this one file should be enough with methods:

to_seed - to convert list of the words into seed and

to_hd_master_key - to generate master xpub/xpriv

It doesn't support further derivations (which require a bit more dependencies), for which I'd suggest using bip32 library.

Answer 3

The following code using the python-bip32 lib can show this information.

from bip32 import BIP32, HARDENED_INDEX

bip32 = BIP32.from_seed(bytes.fromhex("01"))

# get master xpriv and xpub
master_xpriv = bip32.get_master_xpriv()
master_xpub = bip32.get_master_xpub()

print("master_xpriv: " + master_xpriv)
print("master_xpub: " + master_xpub)

# get from specif path 
xpriv_from_path = bip32.get_xpriv_from_path("m/84'/0'/0'/0/1")
xpub_from_path = bip32.get_xpub_from_path("m/84'/0'/0'/0/1")

print("xpriv_from_path: " + xpriv_from_path)
print("xpub_from_path: " + xpub_from_path)